Super conductive bearing

ABSTRACT

A method and apparatus for supporting a rotor in a free state with respect to a stator with superconducting bearings. The apparatus has a rotor with closed rotor loops mounted on the rotor shaft and which are formed of a material having zero electrical resistance at a temperature below a superconductivity transition temperature. A stator encloses the rotor and has closed stator loops formed of the zero electrical resistance material and angularly positioned on the stator about the closed rotor loops. The closed rotor and stator loops are cooled to a temperature below the superconductivity transition temperature of the loop material and energized to create a magnetic flux between the ones of the closed rotor and stator loops. Apparatus for centering and securing the rotor within the stator is released to enable the rotor to move in the free state with respect to the stator.

This is a Division, of application Ser. No. 09/654,964, filed on Sep. 5,2000.

FIELD OF THE INVENTION

The invention relates to superconductive bearings and in particular to amethod and apparatus of operating a structure of a rotor in anequilibrium stable state within a stator by use of superconductivebearings.

BACKGROUND OF THE INVENTION

Bearings have found a widespread use through-out time to enable movementof one mechanical part with respect to another. In one application, abearing structure may enable movement of a wheel with respect to a axisin which a rotary part such as a wagon wheel rotates around a stationarypart such as the wagon axle. In another application, rotating apparatussuch as a rotor is positioned within stationary apparatus such as astator like as in various types of electric motors so that the rotorrotates within the stator. In prior art bearing structures, the constantand long term rotation of a rotating part with respect to a stationarypart causes an undue amount of wear on parts of the rotor and statorthat are in movable contact with each other and thereby may result in anuneven movement of one part with another and even failure of the bearingstructures.

Various techniques have been used to lessen and even prevent the wear ofthe moving parts. Even in very early times the wear problem wasrecognized and various types of lubricants have been applied as a thinfilm between the rotating parts to reduce friction, heat and wear. Inaddition, it was recognized that various types of materials could bedeveloped and used with new lubricants to reduce the wear of the bearingparts and to improve operation of the bearing structures.

Attempts have also been made to suspend a moving part independently of astationary part so as to prevent one part from engaging another andthereby reduce friction, wear and heat. Permanent magnets have been usedin past bearing structures to generate opposing magnetic flux fieldsbetween a housing and an inner rotating member to repulse one movingpart from another. In one such bearing structure, various configurediron rings were alternately mounted with axially magnetized rings onboth a rotor and stator in which like poles on and between the rotor andstator face one and another to provide repulsion between the rotor andstator. A problem arises in this arrangement due to the unevenness inthe fields generated by minor differences occurring in the ringconfigurations. One solution to prevent the minor differences fromoccurring was to install alternate iron rings and radially polarizedmagnets on both the rotor and stator. In another application, magnetswere provided on a bearing rotor and a pair of coils were installed on astator and pulsed to avoid a vibrational resonance condition between thestator and rotor. Another application, was to make a rotor operateindependently of the stator by having one set of rings generating anaxially aligned field and another set of rings generating a radiallyaligned field such that one member was suspended within another withoutcontact. Again, problems exist in these designs due to theinconsistencies in the magnetized members.

Various bearing apparatus in the prior art have been designed to usesuperconducting material to improve operation of a rotor within fixedstators. In one design, a superconducting rotor is constructed with amagnetic pole at each end of the rotor with the poles resting in abearing. A bath cools the apparatus such that the rotor is elevated withrespect to the fixed bearing. Superconducting coils have been used withboth rotor and stator apparatus to develop a repulsive force between thefixed stator and a movable rotor. Methods have been developed forcharging superconductive coils constructed of niobiumtitanium andniobium-tin materials submerged in a cooling agent. Thermocouples, onelocated outside the cooling agent and another located in the coolingagent, are wired in series with the coil and serve to provide a current.One particular bearing structure has circular superconductive coilsmounted within a disk of the rotor and has fixed superconductive coilsmounted within the stator in a plane parallel to a plane of the rotorcoils. The stator coils are positioned directly opposite the rotor coilsand generate a repulsive force. Apparatus has also been developed toachieve a current circulating circuit in the winding of asuperconducting magnet.

Although superconductive bearing apparatus has been developed in theprior art, a problem arises of instability of operation and superconductive bearing apparatus is needed to reduce magnetic fieldinhomogeneities which produce vibration between the stator and rotor insuperconductive bearings.

SUMMARY OF THE INVENTION

It is an object of the invention for a superconductive magnetic bearingstructure to support a rotor with respect to the stator in a free stablestate.

It is another object of the invention for a superconductive bearing tohave a rotor with closed rotor loops each formed of a superconductivematerial having zero electrical resistance at a temperature below asuperconductivity transition temperature.

It is another object of the invention for a superconductive bearing tohave closed stator loops formed of the superconductive material andangularly mounted on a stator around the closed rotor loops.

It is another object of the invention for a superconductive bearing tohave a rotor with closed rotor loops each formed of a superconductivematerial having zero electrical resistance at a temperature below asuperconductivity transition temperature and a stator enclosing therotor and having closed stator loops formed of the superconductivematerial and angularly positioned around one of the closed rotor loopsand cooled below the superconductivity transition temperature toestablish frozen magnetic linkages between the closed rotor and statorclosed loops to form the superconductive bearing supporting a rotationof the rotor in an equilibrium stable state within the stator.

It is another object of the invention for a superconductive bearing tohave two-state switches each having resistive and shorting states foruse with closed rotor and stator loops for enabling energization of theclosed rotor and stator loops to establish frozen magnetic linkagestherebetween.

In a preferred embodiment of the invention, apparatus for supporting arotor with superconducting bearings in a stator has a rotor with a pairof closed rotor loops each formed of a planar short-circuited coil woundof a superconductive wire having zero electrical resistance at atemperature below a superconductivity transition temperature and whichare mounted on a shaft of the rotor at each end of the rotor. A statorencloses the rotor and has closed stator loops formed as planarshort-circuited coils wound of the superconductive wire and areconfigured to have two non-equal circular-arc sides joined at the endsthereof by radial segments and each is angularly positioned at ends ofthe stator around one of the closed rotor loops. A two-state switchhaving a resistive and a short state is formed of coils of wire woundaround a section of the planar short-circuited coils of the closedstator loops. A cooling agent cools the closed rotor and stator closedloops to a temperature below the superconductivity transitiontemperature. Apparatus energizes the cooled closed rotor and statorloops and the two-state switch and establishes frozen magnetic linkagesbetween the closed rotor and stator closed loops and forms asuperconductive bearing supporting a rotation of the rotor in anequilibrium stable state within the stator. Sensors mounted on thestator within a magnetic field zone of the closed stator and rotor loopsfrozen magnetic linkages registers linear shifts and angulardeclinations of the rotor relative to the stator.

In another embodiment of the invention, a planar superconductive bearingstructure has a rotatable member formed as a short-circuited coil woundof a superconductive wire having zero electrical resistance at atemperature below a superconductivity transition temperature. Aplurality of stationary member closed loops are formed as a planarshort-circuited coils wound of the superconductive wire configured tohave two non-equal circular-arc sides joined at the ends thereof byradial segments are each angularly positioned around the closedrotatable member. A cooling agent cools the closed rotatable andstationary member closed loops to a temperature below thesuperconductivity transition temperature. Apparatus energizes the cooledrotatable and stationary member closed loops and establishes frozenmagnetic linkages therebetween forming a superconductive bearingsupporting a rotation of the rotatable member in an equilibrium stablestate within the stationary members.

In another embodiment of the invention, a method of supporting a rotorwithin a stator by superconducting magnetic bearings comprises a step ofarresting the rotor having closed rotor loops with respect to the statorhaving closed stator loops adjacent the closed rotor loops wherein theclosed loops are formed of a superconductive material. The method coolsthe rotor and stator closed loops to a temperature below asuperconductivity transition temperature and establishes a zero electricresistance of the closed loops. The method enables a small portion ofthe cooled rotor and the stator closed loops to assume a resistancestate and applies a current through the resistance state of the cooledrotor and stator closed loops to generate frozen magnetic linkagesbetween the rotor and stator closed loops. The rotor is then freed torotate in an equilibrium stable state within the stator.

BRIEF DESCRIPTION OF THE DRAWING

For a further understanding of the objects and advantages of the presentinvention, reference should be had to the following detaileddescription, taken in conjunction with the accompanying drawing figures,in which like parts are given like reference numerals and wherein:

FIG. 1 is a view of one embodiment of bearing apparatus in accordancewith the principles of the invention,

FIG. 2 illustrates a symbolic representation of the bearing apparatus atroom temperature,

FIG. 3 illustrates a two-state switch used in accordance with thebearing apparatus set forth in FIG. 1 and the symbolic bearing apparatusrepresentation of FIG. 2,

FIG. 4 illustrates the symbolic representation of the bearing apparatusin FIG. 2 at a temperature T₁ below a superconductivity transitiontemperature T_(C),

FIG. 5 illustrates the symbolic representation of the bearing apparatusin FIG. 2 with current applied to the closed stator loops,

FIG. 6 illustrates the symbolic representation of the bearing apparatusin FIG. 2 with current removed from the closed stator loops and withtwo-state switches in the shorting states, respectively.

FIG. 7 illustrates the symbolic representation of the bearing apparatusin FIG. 2 with the rotor freed and with two-state switches in theshorting state and with the rotor positioned in an operational stablestate with respect to the stator by frozen magnetic linkages establishedbetween the bearings closed stator and rotor loops.

FIG. 8 is a view of another embodiment of bearing apparatus inaccordance with the principles of the invention,

FIG. 9 is a view of still another embodiment of bearing apparatus inaccordance with the principles of the invention,

FIG. 10 is a view of yet another embodiment of bearing apparatus inaccordance with the principles of the invention, and

FIGS. 11 through 19 illustrates various constructions of closed rotorand stator loops in accordance with the principles of the invention.

DETAILED DESCRIPTION OF THE INVENTION

In a first exemplary embodiment of the invention, superconductivebearing apparatus 10, in accordance with the principles of theinvention, is shown in FIG. 1 of the drawing. The bearing apparatus 10set forth in FIG. 1 has two magnetic aperconductive magnetic bearingstructures rotatably supporting a rotor 200 in a free state within astator 100. Each bearing structure consists of three closed stator loops101 and one closed rotor loop 202 wherein the cross section of each loopis small compared to the area of the planer loop. The closed statorloops 101, although not limited thereto, may be planar superconductiveshort-circuited coils wound from thin niobium-titanium or niobium-tinwire or similar superconductive material and are angularly mounted atends of the stator around the closed rotor loops 202. Each closed statorloop 101, although not limited thereto, is configured to have twonon-equal circular arc sides 1010 joined at the ends thereof by radialsegments 1011. Three closed stator loops 101 are mounted in a plane ateach end of the stator and are positioned 120° apart around a closedrotor loop 202 to form one superconductive bearing. Each closed rotorloop 202 is a planar short-circuited coil wound from thinniobium-titanium or niobium-tin wire or is formed from a similarsuperconductive material of a superconductive wire and mounted on oneend of the rotor 200.

In an initial state, the rotor 200 is prevented from rotation and isheld in a fixed position with respect to stator 100 by arrestingapparatus. Arresting apparatus may, in one embodiment of the invention,be a cylindrical member 203 having a conical aperture 2030 formedtherein to receive a pointed end of rotor 200 and initially hold rotor200 in a non-rotational and fixed position with regard to stator 100.Other types and configurations of arresting apparatus maybe devisedwithin the spirit and scope of the invention to hold and release rotor200 with respect to stator 100. In operation, cylindrical members 203located at and engaging each end of the rotor 200 are moved outwardalong axis 1000 of rotor 200 and away to disengage the conical apertures2030 from the ends of rotor 200. Rotor 200, in a manner herein afterdescribed in detail, is thereby released to move in a free stable statewith regard to stator 100.

In order to prepare the bearing apparatus of FIG. 1 for operation,certain steps must be fulfilled. First rotor 200, FIG. 2, is heldrelative to stator 100 by the arrester members 203 gripping rotor 200after movement along axis 1000 while the bearing apparatus componentsare at room temperature T. When the room temperature T is maintainedabove the superconductivity transition temperature T_(c), the closedstator loops 101 are symbolically shown as coils 101 u connected tocurrent terminals 152 and 153 with a two state switch 151 shown asconnected across ones of the coils 101 u. Similarly, each of the twoclosed rotor loops 202 positioned at an end of the rotor 200 are eachsymbolically shown as coils 202 u coupled with another two state switch251. The two bearing structures are each represented by the combinationof the closed stator loop coils 101 u and two-state switch 151 with theclosed rotor loop coils 202 u and two-state switch 251 located at eachend of the rotor 200. At room temperature T, the two-state switches 151and 251 are represented in a resistance state.

The closed stator loops 101, FIG. 1, of each bearing structure may beconnected in series as shown in FIG. 2 with outer ends of one of theclosed stator loop coils 101 u connected to current terminals 152 and153. Thus, a current may be applied from a current source to oneterminal 152 and, at room temperature T, flow through coils 101 u of thethree closed stator loops 101 and return to the source by the otherterminal 153. In one embodiment of the invention, FIG. 3, although notnecessarily limited thereto, two-state switch 151 may be constructed ofa coil 1010 u wound around part of a coil winding of ones of the closedstator loop coils 101 u and will operate in a manner hereinafterdescribed in detail to assume states herein represented as a resistanceand a short, respectively.

With the rotor 200 held in a fixed positioned with respect to stator 100by arresting members 203, FIG. 4, the bearing apparatus is cooled by acooling agent to a temperature T₁ below the superconductivity transitiontemperature T_(C) of the closed rotor and stator coil superconductormaterials. With the superconductivity material of the closed stator androtor loops, the resistance decreases as the temperature T₁ decreasesand suddenly drops to essentially zero as temperature T₁ drops below thesuperconductivity transition temperature T_(C). The electricalresistance of the closed rotor and stator loops 101, 202, FIG. 1, willremain at the zero value so long as the temperature condition T₁ is lessthan T_(c) for all parts of the closed loops. Thus, when temperature T₁of the bearing apparatus is below the superconductivity transitiontemperature T_(C), the resistance of the closed rotor and stator loopcoils 202 u and 101 u, FIG. 4, is essentially zero and two-stateswitches 151 of the stator 100 and 251 of the rotor 200 are shown asbeing in the short state.

As set forth in FIG. 3 of the drawing, a current I₁ is applied to theheating coil 1010 u of two-state switch 151. The temperature of thesection of coil winding 101 u surrounded by heating coil 1010 u risesabove the superconductivity transition temperature T_(c), FIG. 5,thereby causing the two-state switches 151 to assume the resistivestate. Current I is then applied to the bearing apparatus via a currentsource 160 connected to the terminals 152 and 153 of the closed statorloops 101 u while the temperature condition T₁ is less than T_(c). Inaccordance with the superconductivity phenomenon, the superconductivityzero resistance of a small portion of the closed stator loops 101 u aredestroyed by the applied current I. Thus, a closed electrical circuitexists for the flow of an electric current. The applied current I andthe flow of the applied current I in the closed stator loops 101 uthereby generate a magnetic flux field between the adjacent closedstator and rotor coils 101 u and 202 u, respectively, attracting theclosed rotor coils 202 u to the closed stator coils 101 u when the rotorcoils 202 u are positioned with respect to the stator coils 101 u. Thegenerated magnetic flux fields generate a current flow in the closedrotor loops 202 u.

After achieving desirable energizing levels for the coils 101 u of theclosed stator loops 101, current I 1 , FIG. 3, is removed from heatingcoils 1010 u to discontinue the heating of the sections of closed statorloop coils 101 u and the current I is removed from terminals 152 and153, FIG. 6. Due to the cooling agent that is continuously cooling thebearing apparatus and the shut off of heating coils 1010 u, thetemperature T₁ is less than T_(C) and the zero electrical conductivitystate as a consequence is restored to the closed stator loop coils 101u. The condition of two-state-switches 151 and 251 corresponds to theshort state and in accordance with the superconductivity phenomenon thecurrent remains in the closed stator and rotor loops 101 and 202 andthey begin to operate in a frozen magnetic linkage mode attracting oneto the other without requiring any additional power.

Additional energizing of some of the closed stator loops may be requiredto provide for the fixed location of the rotor 200 after freeing, ifneeded. After that all of the closed stator and rotor loops 101 and 202become short-circuited, FIG. 6, the superconductive coils 101 u and 202u operate in the frozen magnetic linkage mode with non-zero andnon-equal frozen magnetic linkage for any pair of magneticallyinteracting closed stator and rotor loop 101 and 202. After finalenergizing of the closed stator and rotor loops 101 and 202, FIG. 1,sensors 300 mounted on the stator 100 measure magnetic fields parametersat fixed location of the rotor 200. With the closed stator and rotorloops 101 and 202 linked by the frozen magnetic linkages of the statorand rotor coils 101 u and 201 u, FIG. 7, and the two-state switches 151and 251 in the short state, the arrester members 203 are moved outwardalong rotor axis 1000 to free rotor 200, FIG. 1, thereby enabling rotor200 to rotate in a positional equilibrium stable state with respect tostator 100 within the superconductive bearing structures defined by themagnetically linked and closed stator and rotor loops 101 and 202.

After freeing the rotor 200, the sensors 300 register changes ofmagnetic field parameters and a measuring subsystem that may beconnected with the stator sensors 300 determines linear shifts andangular inclinations of the rotor 200 at its free locations comparedwith its fixed location relative to stator 100. If these shifts andinclinations surpass acceptable shifts and inclinations, the above stepsmay be repeated beginning with moving the arrester members 203 alongrotor axis 1000 to engage the rotor 200. After the required limitationsof shifts and inclinations of the rotor 200 in its free equilibriumlocation are satisfied, the free rotor 200 may be rotated at variousspeeds within its operation range. For each rotor speed, additionalenergizing can be made to limit shifts and declinations for therevolving rotor 200 to acceptable deviations.

Another embodiment of the invention is shown in FIG. 8 of the drawing.The superconductivity bearing apparatus has a number of closed rotorloops 202 each wound as a coil of the superconductive wire or materialaround the rotor 201 and each positioned in a circular plane about theaxis 1000 of the rotor 201 The stator 100 has a number of closed statorloops 101 each wound as a coil of superconductive wire 209 and ones ofwhich are mounted in the stator 100 in a plane around the rotor adjacentto a corresponding one of the closed rotor loops 202. The closed statorloops 101 and rotor loops 202 are positioned in planes perpendicular tothe rotor axis 1000 to form an axial plurality. Any pair of thisplurality, or each superconductivity bearing, consists of six closedstator loops 101 and one closed rotor loop 202 positioned with the sixclosed stator loops 101 surrounding the one closed rotor loop 202. Eachclosed stator loop 101 is a planar superconductive short-circuited coilwound from a thin niobium-titanium or niobium-tin wire 209 orconstructed from other super conductive material. Closed stator loops101 are equipped with the two-state-switch, FIG. 3, and encased in arigid member mounted on stator 100. The planar closed stator loop 101 isconfigured by two non-equal circular arcs and two radial segmentsconnected by smooth curves. Six closed stator loops 101 are equallyangularly spaced in a plane parallel to the rotor axis 1000 such thateach of the six closed stator loops 101 are equally distant from theaxis 1000. Each closed rotor loop 202 is a ring superconductiveshort-circuited coil wound from the thin niobium-titanium or niobium-tinwire 209, or other superconductive material, and equipped with thetwo-state-switch, and encased in a rigid member which is mounted aroundthe rotor shaft 201. In the structure, each superconductivity bearinghas six of the closed stator loops 101 angularly positioned around oneclosed rotor loop 202 and are located in the same plane with othersuperconductivity bearing planes equally spaced along the rotor 201. Inorder to establish the operating conditions for this superconductivitybearing apparatus, the steps as earlier set forth for FIGS. 2 through 7are required.

In another embodiment of the invention, FIG. 9, each closed stator loop101 is an identical coil encased in a rigid member mounted on stator 100and wound from a thin superconductive niobium-titanium or niobium-tinwire 209 or other superconductive material and equipped with thetwo-state-switch, FIG. 3. The closed stator loops 101, FIG. 9, are eachangular spaced and mounted on the stator between ones of the rotorclosed loops 202 so as to be perpendicular to and off-center of therotor axis 1000. Each closed rotor loop 202 is an identicalshort-circuited coil wound from a thin niobium-titanium or niobium-tinwire 209 or other super conductive material and encased in a rigidmember attached to the rotor 201 by a disk 207 positioned along therotor axis 1000. In the arrested position of the rotor, the closed rotorloops 202 are concentric to the rotor axis 1000 and are equally axiallyspaced relative to adjacent closed stator loops 101. The operatingconditions for this bearing apparatus are similar to the preferableembodiment of FIG. 1. In operation, frozen magnetic linkages areestablished between adjacent closed stator and rotor IOUs 101 and 202thereby supporting a rotation of the rotor 201 in an equilibrium stableand free state within the stator 100.

In yet another embodiment, superconductive bearing apparatus, inaccordance with the principles of the invention, has a pair ofsuperconductive magnetic bearings, FIG. 10. Each superconductivemagnetic bearing is composed of three planer closed stator loops 101adjacent one closed rotor loop 202 and may be used with a kinetic energycarrier for flywheel energy storage. The stator 100 comprises a pair ofplanar closed stator loops each having three coils wound ofsuperconductive thin niobium-titanium or niobium-tin wire or formed ofother superconductive material and each coil angularly spaced adjacentto another one of the coils and each of three closed stator loops 101mounted at an end of the stator 100 in a plane parallel to acorresponding one of the closed rotor loops 202 and each equipped with atwo-state-switch, FIG. 3. Each closed stator loop 101, FIG. 10, isformed in a circular arc and two radial segments connected by smoothcurves configuration and are equally angularly spaced in their plane andfrom rotor axis 1000. Closed rotor loops 202 are a ring configuredsuperconductive short-circuited coil wound from superconductor wire andencased in a rigid member mounted in a plane perpendicular to the rotoraxis 1000 on ends of the rotor 200 adjacent to three of the closedstator loops 101. The procedures for preparing this apparatus foroperation are similar to above set forth procedures for the embodimentshown in FIG. 1. In operation, frozen magnetic linkages are establishedbetween the three adjacent closed stator loops 101 and a closed rotorloop 202 thereby supporting a rotation of the rotor 200 in anequilibrium stable free state within the stator 100.

Closed loops as sources of magnetic fields can be represented in variousdesign configurations. A pair of closed stator and rotor IOUs for usewith a superconductive bearing rotor and stator shown in FIG. 11 may befabricated from a wide range of superconductor material. Generally theyform concentric rigid thin current carrying rings 500. Rings 500 areformed in a three-layered plate wherein they are mounted in a heat sink501 secured to a resistive heater 502 and attached to a backing 503. Inanother design, FIG. 12, a current carrying configuration is formed of aplurality of closed stator loops 500 each formed of a superconductivematerial configured to have two non-equal circular-arc sides joined atthe ends thereof by radial segments and having zero electricalresistance at a temperature below a superconductivity transitiontemperature. Closed loops 500 are mounted in a circular configuration ina heat sink 501 which is secured on a resistive heater 502 attached to abacking 503 to form a closed loop network.

FIG. 13 illustrates another concept for the fabrication of closed loops.A thin layer of a resistive heater 502 is deposited on a flat backing503. Next, a first heat sink 501, a thin layer of a good heat conductorlike copper, is deposited on the resistive heater 502. Then a thin filmof a semiconductor material such as a niobium-tin is deposited on theflat surface of heat sink 501 which is then etched to form a pattern ofclosed current carrying loops 500 as pluralities of individual closedcurves and/or a rigid network with meshes of small width loops. Afterdepositing the first layer of IOUs 500, a second heat sink layer 504 isdeposited so that it fills all open areas and covers loops 500 providinga flat surface before next depositing the second layer of closed loops500. Then a third heat sink layer 504 is deposited similarly to thesecond one. The layer sequence is repeated to form a “sandwich” ofcurrent carrying closed loops of identical or unlike loops and with loopcoincidence or not for neighboring layers of closed loops.

In any version of thin film technology, a closed loop 500 intended formounting on a stator or rotor can be fabricated to include a currentcarrier, resistive heaters as two-state-switches, and with heat sinks.In one exemplary example, FIG. 14, a plurality of closed loops 500, eachformed of a superconductive material configured in a squareconfiguration and having zero electrical resistance at a temperaturebelow a superconductivity transition temperature, are formed as a“sandwich” of two webs of closed loops 500 having a square shapepositioned in a mesh. First ones of the closed loops 500 are mounted asa square mesh on an upper surface of a first heat sink 504 and secondones of the closed loops 500 are mounted as a square mesh on an uppersurface of a second heat sink 501 and mounted such that the secondclosed loops 500 are positioned adjacent a lower surface of the firstheat sink 504 to correspond with the first closed loops 500.

Individual square multiple closed loops 500, FIG. 15, can be placed onheat sink 504 and configured in a micron size for typical micronsuperconductive bearing applications. The same scaling convention, FIGS.16 and 17 may be used to form meshes of square and ring configuredclosed loops 500 of thin super conductive current carriers deposited onheat sinks 504.

FIG. 17 shows a design of individual ring current carriers 500 depositedon heat sink 504. Small sizes of closed loops in FIGS. 15 through 17promote the high rigidity of the magnetic bearing because rigidity isinversely proportional to sizes of current carriers. FIG. 18 shows largeconcentric closed rings 501 and small closed rings 500 between the largeclosed rings 501. Large concentric rings 501 configured as closed loopsare responsible for providing large magnetic forces and small rings 500are beneficial in providing high rigidity of a magnetic bearing. FIG. 19illustrates two neighboring layers 504 of closed loops 500 which overlapone another. Similar geometric configurations increases rigidity ofsuperconductivity magnetic bearings due to overlapping of closed loopsin layers of coils. The closed loop configurations set forth in FIGS. 15through 19 may be utilized for the stator and rotor of superconductivitymagnetic bearings.

A variety of sizes, forms and displacements of super conductiveshort-circuited loops can be used for the stator and rotor to providespecific magnetic force interaction in magnetic bearings. The closedloops geometry can satisfy high load requirements by special mutualdisplacements of magnetically interacting closed loops mounted on thestator and rotor. At the same time these mutual displacements mustprovide for the required properties of stable positioning and zerotorque respective to the axis of the stator only. In other respects theycan be arbitrary. Therefore, typical concentric mutual displacement isnot necessary. The invention proposes two types of thenon-concentricity. In one case the non-concentricity is between axes ofthe stator and the magnetic field of the closed stator loops and in thesecond case between the axes of the stator and magnetic fields of theclosed rotor loops. The non-concentricity loop arrangement provides fornon-zero radial derivative of mutual inductance responsible for highrigidity. The invention also proposes special force regimes for magneticforces in the superconductivity magnetic bearings in order to stretch orpress the free rotor in axial and radial directions. These regimes maybe utilized to establish conditions for providing for maximal rigidityof a superconductivity magnetic bearing.

Additional advantages may be achieved by adjustments of locations of thefree rotor while it is in equilibrium and rotating to guarantee reliableperformance over a range of speeds. Using magnetic field sensors, 300,FIG. 1, and a measuring subsystem, of a type well known and which needsnot be shown for an understanding of the invention, can fulfill thisadjustment. The sensors 300 are mounted on the stator and positioned inzones of the closed stator loop magnetic fields so that radial shifts ofthe rotor and angular declinations of the rotor axis are in functionalrelations with the sensors data in a one-to-one correspondence. As anexample, the sensors 300 are located so that their axes of sensitivitiesare parallel to the stator axis and the rotor center of mass is betweenparallel planes containing the sensors 300. The number of sensors 300positioned in each plane is three or more. Sensor data on the magneticfield parameters in each plane indicate the maximal radial rotor shiftsin this plane. Data from sensors 300 in two planes are processed throughthe measuring subsystem to provide the means for accurate determinationof radial shifts of the rotor center of mass and angular declinations.

While the foregoing detailed description has described severalembodiments of superconductive bearing apparatus in accordance with thisinvention, it is to be understood that the above description is merelyillustrative and does not limit the scope of the claimed invention.Particularly, the disclosed superconductive bearing apparatus may havevarious configurations of the stator and rotor in combination withvarious shapes and configurations of stator and rotor closed loops forestablishing magnetic linkages supporting a rotation of the rotor in anequilibrium stable free state within the stator. It is obvious from theforegoing that the facility, economy and efficiency of bearing apparatusmay be substantially enhanced by superconductive bearing apparatus forestablishing magnetic linkages between closed stator and rotor loopsforming a bearing supporting a rotation of the rotor in an equilibriumstable free state within the stator.

1. A method of supporting a rotor within a stator by magnetic bearingscomprising the steps of arresting the rotor having closed rotor loopswith respect to the stator having closed stator loops adjacent theclosed rotor loops wherein the closed loops are formed of asuperconductive material, cooling the rotor and stator closed loops to atemperature below a superconductivity transition temperature andestablishing a zero electric resistance of the closed loops, energizingthe closed loops and establishing a frozen magnetic linkage mode betweenthe rotor and stator closed loops, and freeing the rotor and enablingthe rotor to rotate in an equilibrium stable state within the stator. 2.The method of claim 1 wherein the energizing step comprises the step ofenabling the cooled rotor and the stator closed loops to assume aresistance state.
 3. The method of claim 2 wherein the energizing stepcomprises the step of applying a current around a small part of thecooled rotor and stator closed loops to generate frozen magneticlinkages between the rotor and stator closed loops.
 4. The method ofclaim 3 further comprising the step of registering linear shifts andangular declinations of the rotating rotor with respect relative to thestator.
 5. A method of supporting a rotor within a stator at atemperature lower than a superconductive transition temperature bymagnetic bearings comprising the steps of arresting the rotor havingclosed rotor ring loops formed at each end of the rotor with respect tothe stator having closed stator loops adjacent the closed rotor loopswherein the closed loops are formed of a superconductive material,cooling the closed loops to a temperature below the superconductivitytransition temperature and establishing a zero electric resistance ofthe closed loops, energizing the closed loops and establishing amagnetic linkage made between the closed loops, and freeing the rotorthereby enabling the rotor to rotate in an equilibrium stable statewithin the stator.
 6. The method of claim 5 wherein the energizing stepcomprises the step of applying an electrical current around a small partof the cooled closed loops to generate electric currents in the cooledclosed loops and establish magnetic linkages therebetween.